In recent years, there has been a demand for sensitive materials and structures that can be used to provide biosensors.
In particular, use of the graphene film that substantially changes in electrical characteristics in response to adsorption of or coupling with an atom or molecule on the surface has been studied. A conventional biosensor using the graphene film relies on a change in bulk electron conduction characteristics for detection.
However, the electrical characteristics of the graphene film change in response to adsorption of, or other reactions with, most atoms or molecules, so that it is difficult to locate a detection target substance. To overcome this drawback, the biosensor using the graphene film has to have a surface which only the detection target substance is adsorbed to or coupled with.
Thus, it is difficult for the conventional biosensor to detect a target substance with high sensitivity.